The present invention relates to a microwave oven damper unit provided for the air blower inlet used for cooling the magnetron of the microwave oven with air being sent to the heating chamber.
Conventionally, existing microwave ovens provide any of the following three kinds of heating means; heating with microwave oscillated by a magnetron, a heater provided in the heating chamber, and convection heating that causes the heater-generated heat to circulate inside the heating chamber. The latest tendency indicates that a modern microwave oven can selectively perform any of these heating operations using these means built in together. Such an advantageous combination of these heating means enables the user to easily perform any desired cooking, thus providing more conveniences than before. A conventional microwave oven of this kind is typically designed so that air is internally fed by the blower motor through a number of punched holes on the surface of side panels of the heating chamber. Incoming air first cools the magnetron and peripheral parts before being fed to the heating chamber. A damper unit driven by a damper motor is provided just in front of the punched holes, where the damper is controlled so that it opens and closes the blower inlet connecting with the heating chamber. For example, when microwave heating is performed, the damper opens the blower inlet so that air is allowed to flow into the internal space of both the heating chamber and the blower duct. When heating is performed using either a heater or convection means, the damper is closed so that the cooling air flows only in the direction of the blower duct without being routed to the heating chamber, resulting in better heating efficiency. Cooling air flowing through the blower duct is externally exhausted from the microwave oven. Since the damper is driven by the damper motor by heating means and such a microwave oven must use an independent motor that is used to drive only the damper unit, such a damper mechanism actually counteracts the need for realizing cost reduction.